JP 2014-1719A (Reference 1) discloses an intake device of an internal combustion engine including: an intake manifold including a plurality of intake passages; a partition wall formed between each of the intake passages; an opening and closing valve which is provided in each of the intake passages; a rotation shaft which rotates the opening and closing valve; and a bearing block which is disposed in the partition wall and supports the rotation shaft to be freely rotatable. Here, the opening and closing valve has a soft material having sealing properties in a circumferential edge portion, and is formed to communicate with a flow path by shutting off and being separated from the flow path as the circumferential edge portion abuts against the intake manifold. In addition, by forming a bearing hole in the bearing block and by mounting a ball bearing which receives the rotation shaft on the bearing hole, the reduction of noise of a bearing unit is achieved.
In the intake device of an internal combustion engine of Reference 1, since the bearing hole for mounting the ball bearing on the bearing block is open opposing the opening and closing valve, it is difficult to seal a part at which the circumferential edge portion of the opening and closing valve forms the bearing hole. Therefore, in a state where the opening and closing valve is in a closed state, there is a concern that a fluid leaks from the part at which the bearing hole is formed, and as a result, deterioration of sealing performance of a valve body is caused.
Thus, a need exists for an intake device of an internal combustion engine which is not susceptible to the drawback mentioned above.